Beirut, Lebanon — The United States has proposed a boundary between Lebanon and Israel's maritime economic zones to help end a lingering dispute over rival claims and open up oil and gas exploration in the eastern Mediterranean.

If the idea is accepted by both sides, it will reduce the risk of renewed conflict between the two enemy states and hasten Lebanon’s efforts to begin tapping the billions of dollars of natural gas estimated to be lying beneath the seabed.

The proposal, which was submitted to both countries recently, is a compromise on the overlapping exclusive economic zone (EEZ) boundaries individually submitted by Lebanon and Israel, which left 330 square miles in dispute.

There are major economic interests at stake. The US Geological Survey estimated in March 2010 that the Levantine Basin, which includes the territorial waters of Lebanon, Israel, Syria, and Cyprus, could hold as much as 1.7 billion barrels of recoverable oil and 122 trillion cubic feet of gas. The estimated gas deposit represents about 8.5 percent of known global total deposits, according to an assessment by USGS in June.

“The US has offered some ideas and the parties have them under careful consideration,” said a source familiar with the US proposal who would only discuss the subject under condition of anonymity. “Both sides appear to be interested in an equitable solution, which sums up what international law requires in resolving disputes of this nature.”

The US has been mediating a solution between Lebanon and Israel since mid-2011, partly to neutralize another potential trigger for war, partly to allow both countries to peacefully exploit the fossil fuel wealth beneath the seabed of the eastern Mediterranean, and partly in the hope that US oil companies can secure exploitation contracts.

Gibran Bassil, Lebanon’s energy minister, has claimed that surveys have shown that the area off the southern Lebanon coast alone contains 12 trillion cubic feet of gas, which “could be enough to cover Lebanon’s electricity production needs for the next 99 years.”

Lebanon submitted its proposed EEZ boundary with Israel to the United Nations in October 2010, selecting an endpoint 82 miles out at sea, equidistant between coastal promontories on Cyprus, Israel, and Lebanon – standard cartographic procedure for such cases.

But in July 2011, Israel submitted its own version of the boundary to the UN. Its endpoint lay some 10 miles northeast of Lebanon’s final point, creating a 330 square mile overlap.

The maritime dispute quickly provoked bellicose rhetoric. Israel, which had already moved ahead with parceling up oil and gas concessions in its northern coastal waters, has drawn up a multimillion-dollar plan to defend its interests, while Lebanese Shiite militant group Hezbollah warned the Jewish state to stay out of the disputed zone.

Nabih Berri, the Lebanese parliamentary speaker, said in September that “we will not compromise on any amount of water from our maritime borders and oil, not even a single cup."

However, Najib Mikati, Lebanon’s prime minister, is believed to be supportive of a quick resolution to the dispute. And despite his defiant tone, Mr. Berri has been the most active Lebanese leader in pushing for the exploitation of Lebanon’s off-shore resources, suggesting that the value of the fossil fuel waiting to be tapped will overcome reservations over a compromise with Israel.

Furthermore, new technologies and rising fuel prices are making economically viable many oil and gas reservoirs around the world that were previously considered commercially unattractive. If Lebanon and Israel cannot resolve their EEZ boundary, international oil companies may choose to exploit oil and gas opportunities elsewhere rather than invest in an area that could prove the trigger for a future war.